The invention generally relates to a sensor mount assembly.
Many devices, such as fuel cells, use fluids to conduct heat or perform other functions in the device. Monitoring temperature, pressure and other properties of these fluids may require the use of a sensor. It is desirable that the sensor be mounted in a manner that is inexpensive and easy to manufacture, as well as easy to use.
A fuel cell is an electrochemical device that converts chemical energy produced by a reaction directly into electrical energy. For example, one type of fuel cell includes a proton exchange membrane (PEM), often called a polymer electrolyte membrane, that permits only protons to pass between an anode and a cathode of the fuel cell. At the anode, diatomic hydrogen (a fuel) is reacted to produce hydrogen protons that pass through the PEM. The electrons produced by this reaction travel through circuitry that is external to the fuel cell to form an electrical current. At the cathode, oxygen is reduced and reacts with the hydrogen protons to form water. The anodic and cathodic reactions may be described by the following equations:
H2xe2x86x922H++2exe2x88x92 at the anode of the cell, and
O2+4H++4exe2x88x92xe2x86x922H2 O at the cathode of the cell.
Because a single fuel cell typically produces a relatively small voltage (around 1 volt, for example), several serially connected fuel cells may be formed out of an arrangement called a fuel cell stack to produce a higher voltage. The fuel cell stack may include different flow plates that are stacked one on top of the other in the appropriate order, and each plate may be associated with more than one fuel cell of the stack. The plates may be made from a graphite composite or metal material and may include various flow channels and orifices to route the above-described reactants and products through the fuel cell stack. Several PEMs (each one being associated with a particular fuel cell) may be dispersed throughout the stack between the anodes and cathodes of the different fuel cells. The anode and the cathode may each be made out of an electrically conductive gas diffusion material, such as a carbon cloth or paper material, for example. Besides communicating products and reactants throughout the stack, the flow channels may also communicate a coolant to remove heat from the stack.
The reformate (containing the hydrogen), air and coolant that circulate through a fuel cell stack are examples of working fluids. The temperature and other properties of the working fluids, such as the reformate, may be monitored to maintain desired operating conditions. Ideally, the sensors that are employed for this purpose should be mounted in fixtures that are easy to manufacture, inexpensive, and that allow the sensor to be quickly installed and removed.
In an embodiment of the invention, an assembly includes a receptacle and a sensor body. The receptacle includes an orifice and includes at least one tab for engaging a feature (e.g., a notch) of the sensor body. In another embodiment, the tab may be located on the sensor body and may be adapted to engage a feature of the receptacle. The sensor body is adapted to be inserted into the orifice. The sensor body includes a notch to receive the tab(s) to secure the sensor body in the receptacle and at least one prominence to lift the tab(s) out of the notch to release the sensor body from the receptacle when the sensor body is rotated.